Hello dear forum community,
after posting our Enscape 2.6 release video which you can check out here if you haven't already, we received a few requests from our users when it comes to creating the wet street which you see in the first showcased project in the video.
With this tutorial I'll provide a step by step guide on how you can achieve this effect in Enscape yourself within our supported CAD solutions (Revit, SketchUp, Rhino, ArchiCAD). For this tutorial I'll be using SketchUp.
Be aware that this tutorial is only a general guide - everything explained here can be viewed as guidelines, so feel free to fine-tune for yourself as well. 
Step one (Acquire or generate a tile-able Perlin Noise Texture):
Acquire or generate a so called "Perlin Noise" texture with a tool of your choice. You can also simply Google image search "Perlin Noise tile-able". Make sure that it is actually tile-able by repeating the texture and make sure there are no visible seems.
For this tutorial I've acquired the following tile-able Perlin Noise texture:
[Blocked Image: https://vvvv.org/sites/default/files/imagecache/large/flashPerlin.jpg]
(Credit to xd_nitro)
This one will work just fine for our purpose.
Step two (Acquire a Color texture):
Acquire a high quality texture of your choice, which is also tile-able. The texture being tile-able is not a must - for example if you want to add this effect to one large area only, which will not be tiled. For this tutorial though I'm using the following free-to-use tile-able texture from texturehaven.com:
https://texturehaven.com/tex/?t=cobblestone_color
You can of course use any (tile-able) texture of your choice from this site, or any source / site of your choice!
Now, download the Diffuse texture which is basically the Albedo/Color texture we're looking for in 2k resolution:
I'm using 2k, but you can of course also go for 1k depending on your preferences and tiling configuration. It cannot hurt to have both the Perlin-Noise and Color texture in the same resolution, but in this tutorial we're simply scaling the 512x512 Perlin Texture to fit over the 2k texture. Instead you could also tile the Perlin Texture first and then put it over the 2k Color Texture. More on that later!
Step three (Adjust the Perlin Noise texture and merge it with the color texture):
Now that we have acquired both a Perlin Noise and Color texture, we'll have to make some slight adjustment to the Perlin Noise texture itself, by adjusting the Gamma value. After that, we can merge both the Perlin Noise and Color texture together - for this I'm using the free tool "Paint.net" which is more than capable of doing exactly that.
1. Import the Perlin Noise texture into Paint.net (or any other capable photo editing software of your choice) and adjust the gamma.
Before:
After:
I've used the following Gamma curve adjustment in Paint.net:
Keep in mind that the black (darker) areas will later be represent where the water puddles on the street will be located. (Completely White areas equal no water later in Enscape) So, feel free to fine tune the Gamma curve to your preference!
2. Import the the Color texture into a second layer - we'll now be merging the two textures together!
Make sure that the Color texture layer is above the Perlin Noise like so:
Also, set the Color texture to black and white. In Paint.net simply use the shortcut Ctrl+Shift+G, also make sure you've selected the correct layer.
Now, double-click on the Color texture layer, make sure the Blending Mode is set to Multiply:
This will give you the following merged result:
Above texture can now be saved through Paint.net to be used for both the Roughness and Bump map in Enscape (In Revit: Glossiness map instead of Roughness)! (Above texture is also not in high-resolution, so if you simply want to use this texture without extra effort, please refer to the .zip file attached below which includes all the high-res textures used in this tutorial)
3. (Optional) Merge the Perlin Noise with a Roughness and Bump map each
On the website www.texturehaven.com (or often generally on websites which offer textures) you will also find a corresponding Displacement (Bump) and Roughness texture available for each material. While you can simply merge the Color (Diffuse) Texture with the Perlin Noise, as we've done in the section above, which will then be used as both the Bump and Roughness map in Enscape, feel free to instead merge the Perlin Noise with both the Displacement (Bump) and Roughness map each after downloading them from the site, and import everything as shown/described at the end of "Step four" below.
Be aware: You don't have to take optional these steps, but doing what is described above should give you even more realistic results. If you don't have any Roughness or Displacement (Bump) map available, then using the Color texture will still work perfectly fine.
Step four (Setting everything up in Enscape):
Via the SketchUp / Rhino / ArchiCAD Material Editor:
1. Texture: Import the color texture
2. Bump: Import the merged texture (refer to step three)
3. Reflections: Import the merged texture
Feel free to adjust the Bump Amount to your liking! In this case I'm using 1,30, but this value is customize able to your preference of course.
This is the result in Enscape itself:
Via Revit's internal material Appearance tab:
1. Image: Import the color texture
2. Bump: Import the merged texture
3. Glossiness: Import the merged texture
Be aware: The Glossiness in Revit uses White areas for the parts where water is being displayed, instead of Black areas as with importing the merged texture as Roughness map into SketchUp / Rhino / ArchiCAD. The workaround is to simply click on the merged texture in the Glossiness section, the Texture Editor will pop up and here you can click "Invert Image".
Optional (If Perlin Noise is merged with Bump and Roughness map each (see end of Step Three)):
1. Texture: Import the color texture
2. Bump: Import the merged Bump with Perlin Noise texture
3. Reflections/Glossiness: Import the merged Roughness with Perlin noise texture
